Marine crane particularly designed for handling cargo containers

ABSTRACT

There is disclosed a mobile crane for loading and unloading marine vessels. The crane is mounted for travel on widely spaced apart runway track means extending parallel to the waterside edge portion of a marine pier. The crane comprises a central tower structure supporting a fixed boom extending therefrom in a shoreside direction and a hinged boom supported thereby extending therefrom in a waterside direction. A traveling counterweight means is mounted for travel only over the fixed boom and at a given level and a load supporting means is mounted for greater travel than said counterweight means and travels over both said fixed boom and said hinged boom and at a lower level than said counterweight means. Preferably, the travel of the counterweight means is one-half that of said load supporting means. The counterweight means and the load supporting means are interconnected and preferably by wire rope and sheave means and in a way to provide a two-part reeving system between the load supporting means and the counterweight means. Also, the load supporting means is self-powered and clamping means, preferably hydraulically operated, are carried by said load supporting means to engage or disengage the wire rope means and cause selective traveling movement thereof and of counterweight means secured thereto. The central tower structure carries the boom hoist machinery and the center of mass of such machinery and of the tower structure is waterside of the center line between the runway track means on which the crane travels. The boom hoist machinery is electrically powered and positioning limit switch means are included in the electric circuitry of such hoist machine so that predetermined positions of said traveling counterweight means and said load supporting means must obtain before the boom hoist machinery is operable. The traveling load supporting means carries a rectangular frame which is designed for use in loading and unloading large bulky loads, as cargo containers, from marine vessels which may have a list and/or trim. A power actuated means is provided for determining the angular relation of said rectangular frame to a horizontal plane and thus permitting adjustment thereof to match the particular trim of the marine vessel being loaded or unloaded. Such power actuated means is shown as being hydraulic. A plurality of rope means depend from said rectangular frame and the relative lengths thereof are selectively power actuated to compensate for the list of the marine vessel.

United States Patent 1 Gould 154] MARINE CRANE, PARTICULARLY DESIGNED FOR HANDLING CARGO CONTAINERS [76] Inventor: Charles D. Gould, 8225 Forest Drive, N.E., Seattle, Wash. 98115 [22] Filed: May 28, 1971 [21] Appl. No.: 147,753

[52] US. Cl. ..2l2/l5, 212/49, 214/14,

212/125, 212/129 [51] Int. Cl ..B66c 5/02 [58] Field of Search ..2l2/48, 49, l5, 14; 214/125,

- [56] References Cited UNITED STATES PATENTS 474,494 5/1892 Brown 212/15 3,381,826 5/1968 Durand 212/48 3,532,227 10/1970 Tax ....2l2/l5 3,554,385 1/1971 Munck ..2l2/l5 FOREIGN PATENTS OR APPLICATIONS 1,212,461 3/1960 France ..2l2/48 Primary Examinerl-larvey C. Hornsby Att0rneyClinton L. Mathis [57] ABSTRACT supported thereby extending therefrom in a waterside direction.

1 Mar. 27, 1973 A traveling counterweight means is mounted for travel only over the fixed boom and at a given level and a load supporting means is mounted for greater travel than said counterweight means and travels over both said fixed boom and said hinged boom and at a lower level than said counterweight means. Preferably, the travel of the counterweight means is one-half that of said load supporting means. The counterweight means and the load supporting means are interconnected and preferably by wire rope and sheave means and in a way to provide a two-part reeving system between the load supporting means and the counterweight means. Also, the load supporting means is self-powered and clamping means, preferably hydraulically operated, are carried by said load supporting means to engage or disengage the wire rope means and cause selective traveling movement thereof and of counterweight means secured thereto.

The central tower structure carries the boom hoist machinery and the center of mass of such machinery and of the tower structure is waterside of the center line between the runway track means on which the crane travels. The boom hoist machinery 1S electrically powered and The traveling load supporting means carries a rectangular frame which is designed for use in loading and unloading large bulky loads, as cargo containers, from marine vessels which may have a list and/or trim. A power actuated means is provided for determining the angular relation of said rectangular frame to a horizontal plane and thus permitting adjustment thereof to match the particular trim of the marine vessel being loaded or unloaded. Such power actuated means is shown as being hydraulic. A plurality of rope means depend from said rectangular frame and the relative lengths thereof are selectively power actuated to compensate for the list of the marine vessel.

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M. V |illl Huh W 1 c MARINE CRANE, PARTICULARLY DESIGNED FOR HANDLING CARGO CONTAINERS My invention relates to a traveling crane and one which is particularly designed for use on a pier to load and unload marine vessels, and more particularly one which will handle substantially all types of loads, including but not limited to the bulky and heavy presentday cargo containers. The size and weight of such containers are demonstrated by the fact that containers which are 8 feet wide, 8 feet high, 40 feet long, and weigh in the order of 40 long tons are not uncommon.

Prior art cranes for loading and unloading cargo containers to and from shipboard have the shortcoming of a very limited back reach or an ability to load and unload only over a very limited shoreside area. This very severly limited the area over which the cargo could be stowed and directly reached by the crane in moving the cargo to and from shipboard.

Shoreside marine cranes, of the present type, travel on trackway means disposed parallel to the waterside edge portion of a pier. Also, such cranes have a hinged boom portion, which when not in use extends substantially vertically and thus clear of the waterway and when in use, extends substantially horizontally in a waterside direction and to an extent necessary to reach the most outboard location on a marine vessel on which cargo is to be loaded or unloaded.

One reason for limiting the back reach on prior art cranes was the lack of counterbalancing forces on the waterside of the shoreside rail of the trackway on which the crane travels. The desire for a maximum back reach is present whether the hinged boom is in a horizontal or is in a vertical position and, obviously, the weight and the moment arm thereof on the waterside of a crane is much greater when the hinged boom is horizontal and extends waterside than when said hinged boom extends vertically.

It is an object of my invention to provide a construction whereby the maximum back reach of such cranes is increased substantially over that of prior art cranes.

It is an object to provide a crane having a horizontal center of gravity as near to the center line between the first and second track means of the crane runway as is possible under all operating and idle conditions.

It is an object to provide the combination of a crane with a movable hinged boom which may be in a vertical or in a horizontal position, spaced apart first and second track means extending parallel to the waterside edge portion of a pier, and a central tower structure having its center of mass on the waterside of the center line between said first and second track means.

It is a further object to provide such a crane where the hoisting machinery for moving said hinged boom is carried by the central structure and the center of mass thereof is on the waterside of the center line between said first and said second track means.

It is an object to provide such a crane comprising the combination of a central tower structure; a fixed boom supported by such tower structure and extending in a shoreside direction therefrom; a hinged boom supported by such tower structure and extending in a waterside direction therefrom, said hinged boom having a first and vertically extending position and having a second and horizontally extending position and in a waterside direction; traveling counterweight means mounted for travel over the fixed boom and at an upper level; traveling load supporting means for traveling over both said fixed boom and said hinged boom when the latter is in its horizontal position, and at a level below that of said counterweight means; and an interconnecting means connecting the traveling counterweight means and the traveling load supporting means for travel in opposite directions and with the travel of the counterweight means limited to a portion of that of the load supporting means.

More particularly, it is an object to provide such a crane where the interconnecting means between the traveling counterweight means and the traveling load supporting means comprises wire ropes (hereinafter referred to as ropes or rope means) and sheaves with a two-part reeving system.

A further object is to employ a self-powered traveling load supporting means having clamping means, preferably hydraulically operable, to engage and disengage rope means secured to the traveling counterweight means and to provide sheave means, carried by the load supporting means, to guide the rope means relative to the load supporting means when the clamping means are not engaged.

It is a further object to provide stop means, carried by the hinged end portion of the hinged boom, movable into and out of the path of travel of the traveling load supporting means.

It is a further object to provide a trackway carried by the fixed boom for travel thereon of said counterweight means and two axially aligned track means, one carried by the fixed boom and the other carried by the hinged boom for travel thereon of the traveling load supporting means.

It is a further object to provide a fixed boom comprising laterally spaced girders and a hinged boom comprising laterally spaced girders and to mount said trackways on web portions of said girders.

It is a further object to electrically power said hinged boom and said traveling load supporting means, and to provide electrical interlock between the same, so that said hinged boom and said traveling load supporting means must be in predetermined relative positions before the hinged boom can be powered.

It is a further object to provide electrical interlock means actuated by said traveling counterweight means so that powering of said hinged boom means and of said traveling load supporting means is dependent upon positions of said traveling counterweight means.

It is a further object to provide a rectangular frame suspendedly supported from said traveling load supporting means for use in the loading and unloading of cargo containers from marine vessels which containers, when on shipboard, will have the list and the trim of the vessel and to angularly move said frame, by power, as hydraulic means, to determine the trim thereof to match the trim of the cargo container and to suspend rope means therefrom to engage a cargo container at adjusted lengths to compensate for the list of the cargo container.

Other objects of my invention will become implicit and explicit as the description of my invention proceeds in details in connection with the annexed drawings, wherein like reference numerals refer to like parts, and wherein:

FIG. 1 is an elevational view of a crane embodying my invention;

FIG. 2 is a plan view and taken substantially on broken line 2-2 of FIG. 1;

FIG. 3 is an end elevational view, with the girder end tie removed and with the girders in section, for purposes of clarity;

FIG. 4 is a sectional view taken substantially on broken line 4-4 of FIG. 1;

FIG. 5 is a sectional view taken substantially on broken line 5-5 of FIG. 1;

FIG. 6 is a somewhat schematic plan view taken substantially on broken line 6-6 of FIG. 5;

FIG. 7 is a plan view, with parts in section, and taken substantially on broken line 7-7 of FIG. 5;

' FIG. 8 is an elevational view taken substantially on broken line 8-8 of FIG. 7;

FIG. 9 is an end elevational view of the structure of FIG. 8;

FIG. 10 is a sectional view, with parts in plan, taken substantially on broken line 10-10 of FIG. 5;

FIG. 11 is a fragmentary sectional view showing the slewing bull gear and pinion shown in FIG. 5 and illustrated by dotted lines in FIG. 10;

FIG. 12 is a fragmentary side elevational view, with parts in section, and taken substantially on broken line 12-12 of FIG. 10;

FIG. 13 is an enlarged fragmentary elevational view taken substantially on broken line 13- 13 of FIG. 10;

FIG. 14 is an end elevation, with parts in section, and taken substantially on broken line 14-14 of FIG. 13;

FIG. 15 is a somewhat schematic view illustrating the reeving of the ropes and sheaves, the load supporting carriage means, the counterweight means, the hinged boom, and associated parts;

FIG. 16 is a view similar to FIG. 15 and with the load supporting means and the counterweight means in different positions;

FIG. 17 is a view similar to FIG. 16 but with the hinged boom in its vertical position;

FIG. 18 is an enlarged, fragmentary, elevational view of an area of the hinge between the hinged boom and the fixed boom;

FIG. 19 is a fragmentary elevational view and taken substantially on broken line 19-19 of FIG. 18;

FIG. 20 is a fragmentary plan view and taken substan-tially on broken line 20-20 of FIG. 18;

FIG. 21 is an elevational view and taken substantially on broken line 21-21 of FIG. 18;

FIG. 22 is a fragmentary plan view on a larger scale, with parts somewhat schematically shown, showing a portion of the counterweight means when located at the waterside end portion of the fixed boom and associated limit switch means;

FIG. 23 is an elevational view of the structure of FIG. 22; and

FIG. 24 is a schematic wiring diagram illustrating the correlation between electrically controlled parts herein.

A marine pier 20 is of usual construction to adequately support the crane, hereinafter described, and loads carried thereby as well as loads stored on the pier. Also, the pier 20 has a pier face 22 adjacent which maritime vessels may be berthed on the waterside thereof for loading and unloading the vessels. In accordance with usual practice, crane runway comprises first and second track means or rails 24 which are laterally spaced apart at substantial distances, such as 50 feet. The central tower structure, generally numbered 26, of the crane is supported for traveling movement on runway rails 24 by four trucks 28, one on each lower corner of the tower structure, and each of the trucks 28 is supported by a plurality of wheels, such as eight, in view of the great weights involved. Often cranes of the present invention will have a rated capacity of 40 long tons and the crane itself, unloaded, may weigh as much as 850 short tons.

The central tower structure 26 comprises four vertical portal columns 30 disposed at the four corners of the tower; two spaced portal sills 32 extending parallel to rails 24; two spaced portal girders 34 extending crosswise of the direction of rails 24 and above rails 24 to provide a portal having a substantial clearance, such as 40x43 feet; four vertical intermediate tower columns 36 extending upwardly from columns 30 and which are connected together at the top by four horizontal intermediate column caps 38; four vertical upper tower columns 40 extending upwardly from intermediate tower columns 36; and a horizontal tower cap 42 interconnecting together the upper portions of upper tower columns 40.

A fixed boom member, generally numbered 44, comprises a longitudinally extending, braced span, preferably in the form of two laterally spaced fixed boom girders 46, which have their waterside end portions supported by intermediate tower columns 36 and have their shoreside end portions supported by diagonally and laterally spaced backstays 48 extending therefrom to the tower cap 42.

A hinged boom, numbered generally 50, comprises a longitudinally extending, braced span, preferably in the form of two laterally spaced hinged boom girders 52, which have their shoreside end portions supported by, and hinged to, the waterside end portions of the fixed boom girders 46 by hinge means (not shown) having a hinge axis 54.

The hinged boom 50 may assume a first, and substantially vertical position as shown by dotted lines in FIG. I or may assume a second and horizontal position, as shown by full lines in said figure, with the free end portion extending in a waterside direction. When in said second and horizontal position, the waterside end portion is supported by spaced forestays 56 which extend diagonally from the tower cap 42 to the waterside end portions of hinged boom girders 52. In accordance with usual procedures, backstays 48 and forestays 56 are provided with hinged coupling members 58 intermediate their lengths for conventional reasons. In addition, the hinged coupling members 58 permit folding and unfolding of the forestays 56 as hinged boom 50 is moved into and out of its said first and vertical position.

Also, the hinged boom girders 52 are preferably braced together, as by girder end tie means 59.

Referring also to FIG. 4, each fixed boom girder 46, preferably has an inwardly projecting flange plate portion 60 on which a rail 62 is mounted, thus each rail 62 is directly supported by a web of a girder 46. The spaced rails 62 provide a first trackway extending lengthwise of the fixed boom 44 and over which counterweight means 64 travels. As hereinafter explained, the travel of the counterweight means 64 is limited to travel over the fixed boom 44.

A second trackway comprises spaced rails 66, preferably at a lower elevation than rails 62, carried by lower and web portions of fixed boom girders 46. Rails 66 provide a second trackway extending lengthwise of the fixed boom 44 and over which a traveling load supporting carriage means 68 travels, which will be later explained.

The hinged boom girders S2 of the hinged boom 50 carry rails 70 (FIG. 5), which comprises a third trackway which is axially aligned with the second trackway when the hinged boom 50 extends in a horizontal plane, with its free end portion in its waterside direction, and in its second position. Thus, a continuous trackway, comprising said second and third trackways, is provided when the hinged boom 50 extends in said horizontal plane over which trackway, load supporting carriage means 68 may travel from the shoreside end portion of the fixed boom 44 to the waterside end portion of the hinged boom 50.

The means to cause load supporting carriage means 68 to travel (FIG. comprises a power unit 72, which is preferably an electric motor, carried by carriage means 68. Electric power (such as from an external source) is delivered to the shoreside end portion of the fixed boom 44. Flexible electric conductor means 74 (FIGS. 1, 4 and 5) connects with said source (not shown). A plurality of cross beams 76 (FIG. 2) extend between fixed boom girders 46, extend parallel to each other, and support a trackway 78, which extends lengthwise of fixed boom 44. A plurality of cross beams 80 extend between hinged boom girders 52, extend parallel to each other, and support a trackway 82, which extends lengthwise of hinged boom 50. When the hinged boom 50 extends in its horizontal, waterside and second position, trackways 78 and 82 are axially aligned. When load supporting carriage means 68 is disposed on hinged boom 50 or away from its most shoreside position on fixed boom 44, then electric conductor means 74 is draped in festoon fashion with the spaced portions thereof depending from anti-friction bearing trolleys 84 supported by trackways 78, 82, respectively, carried by booms 44 and 50. Thus, when the load supporting carriage means 68 is at the shoreside end portion of fixed boom 44, the electric conductor means 74 will be draped in substantially vertical folds as shown by dotted lines to the left of FIG. 1 and when said carriage means 68 is to the right thereof, as shown in FIG. 1, the said electric conductor means 74 will be festooned as shown by dotted lines in FIG. 1 and in part shown in FIG. 12.

Referring to FIG. 10, the carriage means 68 carries transmission unit 86 connected with cross shaft 88 carrying carriage drive wheels 90 (see also FIGS. 5 and 12). Upon driving of motor 72 in one direction, carriage 68 travels in one direction and upon driving of motor 72 in the opposite direction, carriage 68 travels in the other direction. While I have shown only two of the wheels 90 being driven, obviously, all four wheels can be driven, when desired, for increased traction. Carriage means 68 may travel over rails 66 on fixed boom 44, when hinged boom 50 is in its vertical and first position, and may travel over both rails 66 and rails 70 when said hinged boom 50 is in its horizontal and second position.

As distinguished from being self-powered (like carriage means 68), counterweight means 64 obtains its traveling power from carriage means 68 and thus, the movements of the two are positively synchronized. While not limited to mechanical means for accomplishing such result but as an illustration of such mechanical means, carriage means 68 tows racking rope means generally numbered 92 and such rope means 92, in turn tows counterweight means 64.

In FIGS. 15, 16, and 17, I have shown a two-part reeving system employing said rope means 92. In said figures, the hinged boom 50 and the fixed boom 44 are illustrated in phantom by dot-and-dash lines, the counterweight means 64 and the load supporting carriage means 68 are somewhat diagrammatically shown, the various parts of the racking rope means 92 are illustrated by single lines, and the various sheaves are shown by circles.

Rope part 94 is dead ended adjacent the location of hinged axis 54 of the hinged boom 50; thence rope part 94 extends in the shoreside direction of fixed boom 44 to, and wraps around sheave means 96 (carried by counterweight means 64); thence rope part 98 extends to the waterside end portion of hinged boom 50; thence rope part 98 is wrapped around sheave means 100 carried by hinged boom 50; thence rope part 102 passes load supporting means 68 (to be engaged or disengaged thereby-the specific details thereof being later discussed in connection with FIGS. 13 and 14); thence, rope part 102 passes below counterweight means 64 to and is wrapped around sheave means 104 (carried by the shoreside end portion of the fixed boom 44); thence rope part 106 wraps around sheave means 108 (carried by counterweight means 64); and thence rope part 110 extends to spring take-up dead end means 112, which is a conventional construction and is carried by the shoreside and portion of the fixed boom 44. While a single two-part rope line operating centrally of counterweight means 64 and load carriage means 68 is possible, a more practical construction will employ two parallel two-part rope lines connected with laterally spaced portions of such means 64 and 68 and thus parallel two-part ropes are shown and like parts are given like numbers.

FIG. 1 shows by dotted lines the hinged boom 50 in its vertical and first position and such position is also shown in more detail in FIG. 18. Structure is provided to maintain the various parts of racking rope means 92 taut, even though the hinged boom 50 may be in its first and vertical position (dotted lines in FIG. 1) or in its second and horizontal position (full lines in FIG. 1), or in positions therebetween.

Referring to FIG. 18, various parts heretofore shown and described are illustrated and numbered, and thus the description thereof is hereby incorporated by reference, as: fixed boom 44, hinged boom 50, hinged axis 54, counterweight means 64, load supporting carriage means 68, sheave means 96, rope part 98, rope part 102, rope part 106, sheave means 108, and rope part 110. As the ropes are duplicated on two sides, as heretofore indicated, only one rope and its associated sheaves will be discussed in connection with FIGS. 14 to 18 and the parallel rope, and associate parts, will be easily understood by such description and by the numbering of like parts with like numbers.

In FIG. 18, a fragment of hinged boom 50 is shown in full lines in its horizontal and second position and by dotted lines in its vertical and first position. The bracket means 114 is shown by similar lines as it is connected with and moves with the hinged boom 50. Bracket means 114 carries sheave means 116, which is out of contact with rope part 102 when the hinged boom 50 is in its horizontal and second position and rope part 102 wraps around sheave means 116, when the hinged boom 50 is in its vertical and first position. Also, bracket means 114 carries sheave means 118 having a guide sheave means 120, the latter having interlocking flanges with the former, so that rope part 98 will be retained between the two against lateral displacement. A cross beam 122 extends between the two girders 46 of the fixed boom 44 and cross beam 122 carries sheave means 124. When the hinged boom 50 is in its vertical and first position, the rope part 98 extends over sheave means 124, and wraps around sheave means 118 and when the hinged boom 50 is in its horizontal and second position, the rope part 98 extends over sheave means 124, and horizontally and through the opening provided by the flange parts of sheave means 118 and 120.

As will appear from FIG. 18, as the hinged boom 50 moves from its horizontal and second position to its vertical and first position, rope part 98 shortens in length as it wraps around sheaves means 118 (the latter moving with the hinged boom 50 and the bracket means 114) and at the same time the interconnected rope part 102 lengthens as it wraps around sheave means 116 (again, a part moving with hinged boom 50 and bracket means 114). The relative positioning of sheave means 118, sheave means 116 on bracket means 114 and the relative positions thereof to the hinge axis 54 are precise so that the amount of shortening of rope part 98 is exactly that of the lengthening of the rope part 102.

Self-powered load carriage means 68 is provided with rope clamping means 126 (shown generally in FIG. and in detail in FlGS. 5, 10, 13 and 14), which comprises a fixed jaw member 128 carried by load carriage means 68 and movable jaw 130 movable into and out of clamping position on rope part 102. A suitable means for operating movable jaw 130 is hydraulic and thus I have illustrated hydraulic cylinder assembly 132 and electrically controlled, hydraulically operated pump unit 134 (FIGS. 10 and 14). When it is desired to cause rope part 102 to travel (and counterweight means 64 connected therewith), rope clamping means 126 is closed by moving movable jaw 130 toward fixed jaw 128 and rope part 102 (secured to load carriage means 68). When it is desired to move load carriage means 68 without causing rope part 102 to travel (and parts connected therewith), the clamping means 126 is moved to release position. When clamping means 126 is moved to release position, then rope part 102 will be stationary while load carriage means 68 moves and to support rope part 102 at such time, sheave means 136, carried by load carriage means 68, is pro-vided.

When the clamping means 126 connects load carriage means 68 with rope part 102, the various rope parts and sheave means connected with rope part 102 will travel and turn. As the counterweight means 64 travels on rails at one elevation and the load carriage means 68 travels on rails at a lower elevation, there is adequate space between the two carriages to accommodate the various traveling rope parts. As a two-part rope reeving exists, the rope part 102 will travel two times that of the sheave means 96 and 108 (and counterweight means 64 connected therewith). Thus, the counterweight means 64 travels only a portion of the travel of load carriage means 68.

In my invention it is essential that the counterweight means 64 travels only a portion of the travel of the carriage means 68 for various reasons. First, it is desirable that the travel of the counterweight means 64 be limited to travel over only the fixed boom 44 and that the travel of the same will not be over the hinged boom 50. Second, if the counterweight travel is so reduced, then the power requirement to move the same is reducedthus, if the travel is reduced by one-half, then the power requirement is reduced to one-fourth. Third, by reducing the said power requirement, the size of the various ropes and tackle required is similarly reduced. Fourth, the design of my crane provides for all desired counterbalancing and, at the same time, with travel of the counterweight means 64 limited to travel only on the fixed boom 44. Fifth, by the use of positioning switches (hereinafter described) actuation of load carriage means 68 and associated parts is prevented unless the counterweight means 64 and associated parts are in proper relative position. In this way proper operating and stability conditions exist before the hinged boom and other structures may be operated.

Referring now to FIG. 5, the load supporting carriage means 68 preferably suspendedly supports load hoist machinery house 138. This house 138 is mounted to rotate relative to the carriage means 68 by bearing coupler means 140. Suitable machinery is housed in load hoist machinery house 138, such as a plurality of control panels 142, preferably four hoist drums 144; electric hoist motor 146; and transmission unit 148. The various control panels 142 provide for control of the operation of motor 146, brake 150, hoist drums 144, machinery house rotating unit 152, hydraulic cylinder means 132, (FIGS. 13 and 14) for gripping or releasing rope part 102, load travel motor 72 (FIG. 10) for controlling travel of carriage means 68, tower travel motor unit means 154 (FIG. 3), hydraulic cylinder means 172 (FIGS. 7, 8 and 9), and hydraulic cylinder means 180 (FIGS. 7, 8 and 9). These various units and controls are shown somewhat diagrammatically as individual choice will determined details thereof.

An operators cab 156 (FIGS. 1, 6, 10 and 12) is suitably attached to machinery house 138 and suitable controls are disposed therein for connection with control panels 142 (FIG. 6) and for manual operation by an operator. Hoist ropes 158 (FIGS. 1, 5, 9 and 12) suspend from each of the four hoist drums 144 (FIG. 6) and each is wrapped about a sheave means 160 (FIGS. 1, 9 and 12) carried by a corner of a conventional spreader 162 (FIGS. 9 and 12). Conventional spreader 162 is attachable and detachable to a conventional cargo container 164 by conventional operating means (not shown). A rectangular frame member 166 (FIGS. 7 and 8) is pivotally supported, as with the bottom portion of the machinery house 138 by a cross pivot means 168. A plurality of guide means 170 are carried by machinery house 138 and slidable engage frame means 166 to prevent undesirable twisting thereof.

As containers 164 are conventionally loaded on a marine vessel with their lengthwise direction extending lengthwise or fore and aft of the vessel, then when a container 164 is suspended by ropes 174 and 158 connected with the corner portions of the frame member 166 and corresponding corner portions of the container, through the spreader 162, tilting of frame member 166 about the axis of cross pivot means 168 will compensate for a nonhorizontal position of a cargo container 164 in a lengthwise direction and the angular positions of the lengthwise direction of the frame member 166 may be adjusted to match the trim of the vessel.

A hydraulic cylinder means 172 is positioned at each of the longitudinal end portions of the machinery house 138 and they are operated conjointly to move the left end portion (as shown in FIG. 8) of the frame member 166 either toward or away from the adjacent end portion of the machinery house 138 and at the same time to move the right end portion of the frame member 166 away from or toward the adjacent end portion of the machinery house 138. Thus, in loading or unloading, the rectangular frame member 166, the spreader 162, and the cargo container 164 can be adjusted so that the trim thereof matches the trim of the marine vessel.

The crosswise dimension of the spreader 162, and the cargo container 164 suspended therebelow, should also match the list of the marine vessel. Each hoist rope 158, after wrapping about its sheave means 160, has a rope part 174 and the two rope parts 174 at each end portion of the frame member 166 connect with opposite end portions of an equalizing lever 176 (FIG. 9). Lever 176 is pivotally mounted by pivot means 178, located at its longitudinal center, to frame member 166. Thus, the two rope parts 174 at each end are connected to opposite end portions of a centrally pivoted lever 176, which lever is pivoted on the frame member 166. The angular positions of the lever 176 are determined by hydraulic cylinder means 180 operated through a lever 182 fixed to equalizing lever 176. By joint operation of the hydraulic cylinder means 180 at each end of the frame member 166, the crosswise angular position of the spreader 162, and the cargo container 164, suspended therefrom, can be adjusted to the list of the marine vessel. An operator in operator cab 156 can operate hydraulic cylinder means 172 and 180 to compensate, respectively, for the trim and list of a cargo container following the trim and list of the marine vessel.

The stowed position of the crane is with its hinged boom 50 vertical (the dash line position of FIG. 1) and with the load carriage supporting means 68 and the counterweight means 64, both at the waterside end portion of the fixed boom 44. Also, each of the clamping means 126 (FIG. 14) is released from a rope part 102; the hydraulically operated and electrically controlled stop bars 184 (FIGS. 18 and 19) are in stopping position and preventing the load carriage means 68 from traveling in a waterside direction off fixed boom 44; the limit switch 200 has been tripped by the counterweight 64 moving to its stated position; and hydraulically operated and electrically controlled stop bar 186 (FIG. 22) is in locking position preventing the counterweight means 64 from traveling in a shoreside directionthe bumper stop 188 (FIG. 18), connected with cross beam 122 and in turn with fixed boom 44,

being in place and preventing movement of thecounterweight means 64 in the opposite direction.

To operate the crane, starting from such stowed position, an operator uses stairways 190 (FIG. 1) to reach boom hoist machinery house 192. In front of this house 192 and at a location, where the operator has maximum visibility of hinged boom 50 and its environs, is located a boom hoist control station 194 comprising appropriate electrical control means for controlling the raising and lowering of hinged boom 50. Conventional safety latching means, not shown, are provided to latch and unlatch hinged boom 50 in its vertical position. In other words, when hinged boom 50 is in its stowed vertical position, it is held in place by a safety latch means which must be released before the boom can be lowered. Also, electric boom hoist motor 196, shown schematically in FIG. 24, includes in its operating circuitry, control means located at station 194. Such motor 196 is the power means for moving hinged boom 50 to and from either its full-line horizontal position or its dotted-line vertical position, both as shown in FIG. 1 of the drawings. The operator will first release any latching mechanism nd then controls the operation of motor 196 lowering boom 50 because of the then closed positions of various switches, namely, 200M, 254, 217, 204, and 206. These switches will be closed and permit the operator to energize the electric circuitry to boom hoist motor 196 as said limit switches are closed by reason of the following conditions: counterweight means 64 is in its waterside end position on boom 44, tripping a limit switch 200 having therein contacts 200M and 200C; counterweight stop bar 186 is in its stopping position (by operation of solenoid control unit 244$), tripping limit switch 217 (FIG. 22); load carriage stop bar means 184 is in its stopping position (by reason of solenoid control unit 234$), tripping limit switch 204 (FIG. 19); and rope clamp means 126 is in clamping position (by reason of solenoid control unit 214R), tripping limit switch 206 (FIG. 14). As the description later proceeds to reach the end of the cycle (which is the now starting position), it will be apparent why each of the above-mentioned switches was tripped.

After hinged boom 50 is lowered to its horizontal, second, or full-line position of FIG. 1, the operator can descend stairway 190 and enter operators cab 156. He can cause load carriage means 68 to move to the shoreside end position of fixed boom 44. At such location, the load carriage means 68 will engage and trip limit switch 198, shown diagrammatically on the lower left corner of FIG. 16 and on FIG. 24. This limit switch 198 is connected with contacts 200C of limit switch 200. Limit switch 200 has been tripped because of the position of counterweight means 64 at the waterside end of fixed boom 44. Conductor means 208 and 209 connect limit switch 198 between contacts 200C and set switch 210. Closing of set switch 210 energizes solenoid control switch means 212S through conductor means 216. Referring now to FIG. 14, electrically controlled, hydraulically operated pump unit 134 (see also FIG. 10) is a standard unit readily obtainable on the market and comprises an electric motor, a hydraulic pump, and a four-way valve unit operated by two electrical solenoids. Upon energizing of solenoid valve unit 2128, the valve mechanism will move to cause jaw to move into set or clamping position relative to rope part 102. As will later appear, upon energizing of solenoid valve unit 214R, the valve mechanism will move to cause jaw 130 to move to release or unclamped position relative to rope part 102.

Upon closing of clamping means 126, position limit switch 218 (FIG. 14) is tripped by arm 220, carried by movable jaw 130 of clamping means 126, engaging a lever 222 of limit switch 218. Limit switch 218 has conductor means 224 in the electrical circuitry between solenoid control unit 212S (see also FIG. 14) and solenoid control valve unit 230R (see also FIG. 19). The stop bar means 184 were in stopping position to prevent the load carriage 68 from traveling off the waterside end portion of the fixed boom 44 during the stowed position with the hinged boom 50 in vertical position. With the lowering of the hinged boom 50 to horizontal position, it is desired to move such stop bar means 184 out of stopping position relative to said load carriage 68. This occurs with the energizing of the circuitry including conductor means 232.

Stop bar means 184 are hydraulically actuated by hydraulic cylinder means 226 (FIG. 19) and by electrically controlled, hydraulically operated pump unit 228, which is substantially the same as the previously mentioned pump unit 134 for operating clamping means 126. Upon energizing of solenoid valve unit 230R, the stop bars 184 move to release position. Also, for purpose hereinafter explained, when the solenoid control valve unit 2348 is energized, the stop bars 184 move to set or blocking position. When the stop bars 184 move to release position, limit switch 236 is closed. The switch 236 is between conductor means 232 and 238. Upon energizing of conductor means 238, solenoid unit 240R is energized (see also FIG. 22) which operates electrically controlled hydraulically operated pump unit 242 and moves stop bars 186 out of stopping position relative to the counterweight means 64. The pump unit 242 is similar to pump units 228 and 134. Also, pump unit 242 has a set solenoid control unit 2445, which will be later described. As the stop bars 186 move out of stopping position, limit switch means 246 is energized through conductor means 248, and in turn signal lamp means 250 is energized through conductor means 252. Upon the illumination of signal lamp means 250, the operator knows that the load supporting means 68 is at the shoreside end portion of fixed boom 44 (limit switch 198 being tripped); that the counterweight means 64 is at the waterside end portion of the fixed boom 44, limit switch 200 (contacts 200M and 200C thereof) being tripped; that set switch 210 is closed (he manually closed the same); clamping means 126 has been set (limit switch 218 beingtripped); that stop bars 184 have been retracted and out of stopping position relative to the load carriage 68 (limit switch 236 being tripped); and that stop bar means 186 has moved out of stopping position of the. counterweight means 64 (limit switch 246 being tripped). Thus, the crane is ready for operation of the load carriage means over both the fixed boom 44 and the hinged boom 50 and movement of the counterweight means 64 only over the fixed boom 44.

This position of hinged boom 50 generally continues so long as the ship is berthed at the waterside edge portion of marine pier and is being loaded or unloaded. When this ceases, then the hinged boom is moved to its vertical position (dash-line position of FIG. 1) to eliminate any obstruction of the waterway adjacent the pier 20.

The hinged boom 50 may be moved to its vertical position for placing the crane in its stowed position or in such position for: relocating cargo on the back storage area (within the reach of the load carriage means 68 when supported on the fixed boom 44; loading freight cars or trucks with cargo unloaded from the marine vessel; and storing cargo being delivered by freight cars or trucks to the area adjacent the crane. In order to place the crane in condition for such operation with the hinged boom vertical, the operator will continue as next described.

He will cause the load carriage means 68 to travel to the shoreside end portion of the fixed boom 44. Due to the fact that the load carriage means 68 and the counterweight carriage means 64 are physically interconnected by racking rope means 92, the counterweight carriage means 64 must travel to and be located at the waterside end portion of the fixed boom 44 and in such position will trip limit switch 200 (moving contacts 200M thereof to closed position). If there should be any rope trouble, such as rope stretching or slippage, then such must be corrected before continuation of the cycle as the load carriage 68 must move the counterweight carriage means to the position indicated to trip the limit switch 200.

Next, the operator will manually close clamp release button 254 which is connected to limit switch 200 by conductor means 253 and with solenoid control unit 2445 (see also FIG. 22) by conductor means 256. Upon energizing of unit 244S, counterweight stop bars 186 are extended to set or stopping position relative to the counterweight carriage 64 and limit switch 217 is tripped, which is connected with the solenoid unit 2448 by conductor means 258. Upon tripping of the limit switch 217, solenoid control unit 234S is energized through conductor means 259. Energizing of solenoid control unit 234$ moves load carriage stop bars 184 to extended or set position (FIG. 19). This provides a stop to prevent the load carriage 68 from moving in a waterside direction off the fixed boom 44. Such movement of the stop bar means 184 trips limit switch 204 through conductor means 260. Tripping of limit switch 204 energizes solenoid control unit 214R through conductor means 262 and releases rope clamp means 126. Releasing of rope clamp means 126 permits subsequent travel of the load carriage means 68 and with the counterweight means 64 remaining fixed in its position at the waterside end portion of the fixed boom 44. Releasing of rope clamp means 126 trips limit switch 206 through conductor 264 (FIG. 14). Conductor means 266 connects between limit switch 206 and electrical contactor means 268. Conductor means 270 connects between contactor means 268 and electric motor 196 employed for raising and lowering of hinged boom 50. The successful completion of the various conditions just described are evidenced to the operator by the illumination of the signal lamp means 272 connected with electrical contactor 268.

As the operator has moved the counterweight carriage 64 to the waterside end portion of the fixed boom 44 and locked the same in said position, and further has released rope clamping means 126 from the racking rope means 92, he can now move the load carriage 68 (without moving the racking rope means 92 and in turn the counterweight carriage 64) to the waterside end portion of the fixed boom 44 and then he can move up the stairway 190 and to the boom hoist control station 194. He can then raise hinged boom 50 to its vertical position and thereafter securely set the same in place by employing available boom latches and thus stow the hinged boom 50 in its said vertical position.

Thereafter the operator may return to the operator's cab 156 and operate the load carriage 68 only over the fixed boom 44 and with the counterweight carriage 64 fixed at the waterside end portion of the fixed boom 44. Thus, the fulcrum tipping axis of the crane assembly during such operation will be the shoreside runway rail 24 whenever the load carriage means 68 is shoreside of such shoreside runway rail 24. The operator may continue such. operations for the period desired and thereafter move the load carriage means 68 to the waterside end portion of fixed boom 44 for stowing of the same. Another cycle or part thereof may be commenced from this position in the manners previously described.

When the hinged boom 50 is in its horizontal or fullline position of FIG. 1 and the load carriage means 68 and the counterweight carriage means 64 are properly interconnected through racking rope 92, then when the load carriage means 68 moves in a shoreside direction up to but not shoreside of the shoreside rail 24, then the tipping fulcrum axis of the crane assembly will be the waterside runway rail 24. When the load carriage means 68 is operated shoreside of the shoreside runway rail 24, then the tipping fulcrum axis of the crane assembly becomes the shoreside runway rail 24.

When the hinged boom 50 is in its vertical position (full-line position of FIG. 1) and the counterweight carriage 64 is in its locked position at the waterside end portion of the fixed boom 44, then the tipping fulcrum axis of the crane assembly becomes the shoreside runway rail 24 regardless of the position of the load carriage means 68 on the fixed boom 44.

Further safety features of a crane embodying my invention will become apparent after the description of a crane constructed in accordance with my invention. Such a crane has the following computed specifications. The distance between the runway rails 24 is 50 feet, the total weight is 768 short tons (not including the weight of the counterweight carriage 64); maximum back reach of the crane is 100 feet; maximum outreach is I33 feet; height clearance under the boom 99 feet; weight of the counterbalance means 64 is 75 short tons; weight of central tower structure 26 is 305 short tons; horizontal center of mass of the central tower structure is 6.1 feet waterside of the center line between the runway rails 24; rated capacity of the crane, 40 long tons; hoisting machinery means carried by hoist control house 192, 52 short tons; and horizontal center of mass of the hoisting machinery means is 7.27 feet waterside of center line between the runway rails 24.

Such a crane, because of the features herein described has stability characteristics better than those commonly specified for present-day cranes. For example, with the hinged boom 50 in its horizontal position and with the load carriage 68 at 133 feet outreach (133 feet waterside direction on hinged boom and with 200 percent of rated live load, and with an operating wind of 10 lbs. per square foot, then the crane has a stability factor of 1.078 about the center of the waterside runway rail 24. With the crane in stowed position (hinged boom 50 vertical and load carriage 68 and counterweight carriage 64, both at the waterside end portion of the fixed boom), without live load and with a 30 lbs. per square foot wind on the waterside elevation of the crane, the stability factor is 1.86 about the center of the shoreside runway rail 24. With the hinged boom vertical, the counterweight carriage 64 fixed at the waterside end portion of fixed boom 44, the load carriage 64 extended I00 feet shoreside on fixed boom 44, with 200 percent rated load, plus a 10 lbs. per square foot wind, the stability factor is 1.22 about the center of the shoreside runway rail 24. When the trucks 28 have eight wheels at each corner of the central tower 26, the maximum static load per wheel, when handling I00 percent rated load, is computed at 88.6 kips (44.3 short tons), whether the load is at the maximum outreach or the maximum back reach of the crane, indicating an ideally balanced condition for a crane.

From the foregoing, it will now become apparent that I have provided a crane for use on a marine pier 20 comprising a central tower structure 26, which supports a fixed boom 44. Hinged boom 50 is hingedly supported by the tower structure 26 along hinge axis 54. The hinged boom 50 may extend in a vertical plane when in its first position, shown by dash lines in FIG. 1, and may extend in a horizontal plane when in its second position, shown by the full lines in FIG. 1. Counterweight carriage means 64 is mounted for traveling movement only over over fixed boom 44, as on rails 62. Such limited travel is to be distinguished from the travel of load supporting carriage means 68 which is mounted for travel over both the fixed boom 44 and the hinged boom 50, such as on rails 66 and 70, respectively. The counterweight means 64 and the load supporting carriage means 68 are interconnected in such a way that they travel in opposite directions and the travel of the counterweight means 64 is only a portion of the travel of the load supporting carriage means 68. Preferably, such portions of travel of the counterweight means 64 to that of the load supporting carriage means 68 is one-half and this is illustrated as being accomplished by racking wire rope means 92, and sheave means 96, 100, 104, and 108 employing a two-part reeving system of said racking rope means 92.

Preferably, the load supporting carriage means 68 is self-propelled, as by motor 72, and carries rope clamp means 126 for engaging and disengaging the wire rope racking means 92, and more specifically the rope part 102 thereof. Preferably, such clamping means 126 is hydraulically operated and electrically controlled. Also, the load supporting carriage means 68 carries a sheave means 136, which relatively supports rope part 102 when the same is not engaged by the clamp means 126.

Stop means 184 is preferably carried by the waterside end portion of the fixed boom 44 and is moved into stopping position relative to the load supporting carriage means 68 before the hinged boom 50 can be moved to its vertical (first) position and is moved out of such stopping position before the hinged boom 50 can be moved to its horizontal (second) position.

The central tower structure 26 is supported by runway rails 24 comprising first and second spaced apart, parallel, track means disposed on the marine pier and the center of mass of the central tower structure 26 is disposed in a waterside direction of the center line between the said two tracks of the runway rails 24. Also, the boom hoist machinery means carried by the boom hoist control house 192 is disposed with the horizontal center of mass thereof waterside of the center line between the runway rails 24.

The fixed boom 44 comprises two laterally spaced girders 46 and the first track means 62 is carried by top flanges on such girders 46 and the counterweight means 64 travels thereon. Also, lower web portions of the girders 46 carries rails 66 and the load supporting carriage means 68 travels on such rails while traveling on said fixed boom 44. The hinged boom 50 comprises laterally spaced girders 52 and rails 70 are carried by lower portions of such girders 52. The rails 70 and the rails 66 are axially alined, when the hinged boom 50 is in its horizontal (second) position so that the load supporting carriage means can travel, at such times, over both the fixed boom 44 and the hinged boom 50. The counterweight means 64 and the load supporting carriage means 68, each has wheels to travel over the respective rails associated therewith. The said lower portions of the girders 46 and 52 comprise lower web portions thereof.

Hinged boom 50 is electrically powered and movable from its second and horizontal position (full line position shown in FIG. 1) to its first and vertical position (dash line position shown in FIG. 1) by electric motor 196; load supporting means 68 is electrically powered by the motor 72; and position limit switch 200 must be tripped by counterweight carriage means 64 and stop bars 186 must be set to lock counterweight carriage 64 against travel to trip limit switch 217 before the hinged boom may be raised or lowered. To trip such limit switches 200 and 217, the counterweight means 64 must be at the waterside end portion of the fixed boom 44 and must be locked against travel by the stop bars 186 and the bumper stop 188.

A rectangular frame member 166 is pivotally supported by cross pivot means 168 and in turn by load hoist machinery house 138. Power means, comprising guide means 170 and hydraulic cylinder means 172 at each end of the frame, angularly position frame member 166 to a horizontal plane, thus adjusting the rectangular frame member 166 to match the trim of the marine vessel.

Four powered hoist drums 144 are carried by hoist machinery house 138 and provide four depending hoist ropes 158. Each of these ropes 158 extends around a sheave means 160, supporting a rectangular spreader 162 at the four corners thereof. The ropes 158, after leaving sheave means 160, are rope parts 174, two of. which connect to opposite end portions of each equalizing lever 176. Each equalizing lever 176 is angularly moved by hydraulic cyiinder means 180 and thus the spreader 162 is adjusted to match the list of a marine vessel. Each hydraulic cylinder means 180 is pivoted to a lever 182 which in turn is rigid with an equalizing bar 176.

Obviously, changes may be made in the forms, dimensions and arrangements of the parts of my invention, without departing from the principles thereof, the

foregoing setting forth only preferred forms of embodiment of my invention.

I claim:

1. A crane for use on a marine pier comprising a central tower structure; a fixed boom supported by said central tower structure; a hinged boom hingedly supported by said central tower structure at one end portion thereof, said hinged boom extending in substantially a vertical plane when in a first position and extending in a horizontal plane and in a waterside direction when in its second position; traveling counterweight means mounted for travel over said fixed boom; traveling load supporting means mounted for travel over said fixed boom and over said hinged boom, when the latter is in its second position; and interconnecting means connecting said traveling counterweight means and said traveling load supporting means for travel in opposite directions and limiting the travel of the counterweight means to a portion of that of the load supporting means and to travel over said fixed boom.

2. The combination of claim 1, wherein said portion of travel of the counterweight means to that of the load supporting means is one-half.

3. The combination of claim 1, wherein said interconnecting means comprises wire rope and sheave means interconnecting said counterweight means and said load supporting means.

4. The combination of claim 3, wherein said wire ropes and sheaves employ a two-part reeving system.

5. The combination of claim 3, wherein the sheave means comprises sheave means carried by said traveling load supporting means and said wire rope means passes over said sheave means.

6. The combination of claim 1 of stop means movable into and out of the path of travel of said traveling load supporting means, carried by the hinge end portion of said hinged boom, and moves into the path of travel of the traveling load supporting means, as the hinged boom moves to its first position and moves out of said path, as the hinged boom moves to its second position.

7. The combination of claim 1 with a crane runway first track means disposed on said pier and extending parallel to the waterside edge portion of said pier; a crane runway second track means disposed on said pier in parallel and substantial spaced relation to said first trackway means; and a central tower structure characterized by having its horizontal center of mass disposed waterside of the center line between said first and said second track means.

8. The combination of claim 1 with a first crane runway track means disposed on said pier and extending parallel to the waterside edge portion of said pier; a second crane runway track means disposed on said pier in parailei and spaced relation to said first track means; hoisting machinery means for operating said hinged boom, carried by said central tower structure and disposed thereon with its horizontal center of mass disposed waterside of the center line between said first and second track means.

9. The combination of claim 1, wherein said traveling load supporting means is self-powered; wire ropes are connected with said counterweight means; electrically controlled rope clamps are carried by said traveling load supporting means; and electrical interlock limit switches are disposed in the electrical circuit powering said rope clamps and positioned to be tripped by said traveling counterweight means at a predetermined position thereof.

10. The combination of claim 9 with counterweight means stop bar means for securing said counterweight means at a predetermined location, electrical limit switch means tripped by said counterweight means at a predetermined position thereof, and an electric circuit for said electrically controlled rope clamps including therein said limit switch means.

11. A crane for use on a marine pier comprising a central tower structure; a fixed boom supported by said central tower structure; an electrically powered hinged boom means hingedly supported by said central tower structure and movable from a second horizontal position to a first vertical position; a traveling counterweight means mounted for travel limited to over said fixed boom; an electrically powered traveling load supporting means mounted for travel over said fixed boom and over said hinged boom when in its second position; interconnecting means connecting said traveling counterweight means and said traveling load supporting means for travel in opposite directions and limiting the travel of the counterweight means to a portion of that of the load supporting means; and electrical interlock means limiting electrical energizing of said electrical powered hinged boom means until predetermined positions are reached by said traveling means.

12. The combination of claim 11, wherein said electrical interlock means limits powering of said electrically powered hinged boom means until said traveling counterweight means is in a predetermined position at the waterside end portion of the fixed boom.

13. The combination of claim 11, wherein said electrical interlock means limits powering of said electrically powered hinged boom means until said traveling counterweight means is in a locked position at the waterside end portion of the fixed boom.

14. The combination of claim 11 with a traveling load supporting stop bar means for limiting travel of the traveling load supporting means past a predetermined station, electrical limit switch means tripped by said traveling load supporting means at a predetermined position thereof, and an electrical circuit connecting said limit switch means with said electrical interlock means. 

1. A crane for use on a marine pier comprising a central tower structure; a fixed boom supported by said central tower structure; a hinged boom hingedly supported by said central tower structure at one end portion thereof, said hinged boom extending in substantially a vertical plane when in a first position and extending in a horizontal plane and in a waterside direction when in its second position; traveling counterweight means mounted for travel over said fixed boom; traveling load supporting means mounted for travel over said fixed boom and over said hinged boom, when the latter is in its second position; and interconnecting means connecting said traveling counterweight means and said traveling load supporting means for travel in opposite directions and limiting the travel of the counterweight means to a portion of that of the load supporting means and to travel over said fixed boom.
 2. The combination of claim 1, wherein said portion of travel of the counterweight means to that of the load supporting means is one-half.
 3. The combination of claim 1, wherein said interconnecting means comprises wire rope and sheave means interconnecting said counterweight means and said load supporting means.
 4. The combination of claim 3, wherein said wire ropes and sheaves employ a two-part reeving system.
 5. The combination of claim 3, wherein the sheave means comprises sheave means carried by said traveling load supporting means and said wire rope means passes over said sheave means.
 6. The combination of claim 1 of stop means movable into and out of the path of travel of said traveling load supporting means, carried by the hinge end portion of said hinged boom, and moves into the path of travel of the traveling load supporting means, as the hinged boom moves to its first position and moves out of said path, as the hinged boom moves to its second position.
 7. The combination of claim 1 with a crane runway first track means disposed on said pier and extending parallel to the waterside edge portion of said pier; a crane runway second track means disposed on said pier in parallel and substantial spaced relation to said first trackway means; and a central tower structure characterIzed by having its horizontal center of mass disposed waterside of the center line between said first and said second track means.
 8. The combination of claim 1 with a first crane runway track means disposed on said pier and extending parallel to the waterside edge portion of said pier; a second crane runway track means disposed on said pier in parallel and spaced relation to said first track means; hoisting machinery means for operating said hinged boom, carried by said central tower structure and disposed thereon with its horizontal center of mass disposed waterside of the center line between said first and second track means.
 9. The combination of claim 1, wherein said traveling load supporting means is self-powered; wire ropes are connected with said counterweight means; electrically controlled rope clamps are carried by said traveling load supporting means; and electrical interlock limit switches are disposed in the electrical circuit powering said rope clamps and positioned to be tripped by said traveling counterweight means at a predetermined position thereof.
 10. The combination of claim 9 with counterweight means stop bar means for securing said counterweight means at a predetermined location, electrical limit switch means tripped by said counterweight means at a predetermined position thereof, and an electric circuit for said electrically controlled rope clamps including therein said limit switch means.
 11. A crane for use on a marine pier comprising a central tower structure; a fixed boom supported by said central tower structure; an electrically powered hinged boom means hingedly supported by said central tower structure and movable from a second horizontal position to a first vertical position; a traveling counterweight means mounted for travel limited to over said fixed boom; an electrically powered traveling load supporting means mounted for travel over said fixed boom and over said hinged boom when in its second position; interconnecting means connecting said traveling counterweight means and said traveling load supporting means for travel in opposite directions and limiting the travel of the counterweight means to a portion of that of the load supporting means; and electrical interlock means limiting electrical energizing of said electrical powered hinged boom means until predetermined positions are reached by said traveling means.
 12. The combination of claim 11, wherein said electrical interlock means limits powering of said electrically powered hinged boom means until said traveling counterweight means is in a predetermined position at the waterside end portion of the fixed boom.
 13. The combination of claim 11, wherein said electrical interlock means limits powering of said electrically powered hinged boom means until said traveling counterweight means is in a locked position at the waterside end portion of the fixed boom.
 14. The combination of claim 11 with a traveling load supporting stop bar means for limiting travel of the traveling load supporting means past a predetermined station, electrical limit switch means tripped by said traveling load supporting means at a predetermined position thereof, and an electrical circuit connecting said limit switch means with said electrical interlock means. 